Are Wrist Blood Pressure Monitors Accurate? Can We Go Cuffless?

The skeptical cardiologist spruced up and updated The Skeptical Cardiologist’s Guide to Home Blood Pressure Monitoring today. Most of what I wrote then is still accurate and I am still using home-measured BPs (for those capable of doing the measurements) as my primary tool for BP assessment and management.

However, consumer and industry interest in wrist-based BP monitors has grown substantially in the 4 years since that was published I believe we need to reconsider their utility. Until recently, I was in agreement with the AHA recommendation to choose upper arm-based BP cuffs over wrist-based ones unless the arm cuff was too painful or there was a medical contraindication to it.

In 2020 Omron asked me to evaluate their HeartGuide BP “watch” and although it had potential, ultimately I could not recommend it. I wrote a (somewhat) humorous and whimsical post on my initial experience with the device (Omron’s Omron’s HeartGuide Wristwatch Blood Pressure Monitor Allows BP Monitoring During Daily Activities Unobtrusively: Can It Replace Ambulatory BP Monitors? ) followed by in depth analysis here.

In the end, I found this device too big, bulky, and expensive to be practical. In terms of accuracy, it was, like many wrist BP cuffs, also limited:

I found that the HeartGuide systolic blood pressure was on average 10 mm Hg lower than the brachial BP when my blood pressure was high (>140 mm Hg).  When my systolic BP was between 120 and 130 mm Hg the HeartGuide was 5 mm Hg lower than the brachial and when my blood pressure was less than 120 mm Hg the Heart Guide and brachial BPs were identical.

I made similar measurements on other volunteers and found some had consistently identical wrist and brachial SBP whereas others had consistently higher blood pressures by wrist compared to brachial techniques.

Because of this individual variation I highly recommend users calibrate the OHG (or any wrist-based BP cuff) versus a standard BP cuff over a series of days with multiple measurements to see how the two measurements compare. If you find a consistent over or underestimate then the device can be used with this known adjustment.

Consumer Reports also finds the Omron HeartGuide to be inaccurate and gave iHealth’s wrist BP monitor a very low score for accuracy.

I advise patients to buy BP monitors which are approved by the AMA and on the US Blood Pressure Validated Device Listing.

There are lots of arm BP monitors on this listing but only 4 wrist devices, all by Omron (one of which, the BP8000-M is the aforementioned HeartGuide wristwatch.)

The Omron BP 6100 is also on the validated BP device list. You can read about my friend Wally’s (mostly negative ) experience with the Omron BP6100 here.

Note that the AMA Validated BP Device List has this disclaimer on all the approved wrist cuffs:

Going Cuffless

Wouldn’t it be nice if we could dispense with those noisy, slow, bulky cuffs that BP devices employ as part of the oscillometric determination of blood pressure at either the radial (wrist) or brachial (arm) artery? It would be even nicer if those smart wearable devices (smartwatches and fitness trackers) that have appeared on so many wrists to measure steps and heart rate could also measure BP.

These smart wearables utilize photoplethysmography (PPG) to calculate heart rate and detect irregular rhythms. Many vendors have been exploring other cardiovascular physiologic parameters that can be obtained from the PPG signal including blood pressure.

For a summary of the technology involved in converting PPG signals into important physiologic parameters, I recommend Peter Charlton’s article in the Proceedings of the IEEE.

Despite a lack of validation, a 2020 paper found that in Australia these cuffless wearable devices dominated the online home BP monitor marketplace.

Nonvalidated Home Blood Pressure Devices Dominate the Online Marketplace in Australia: Major Implications for Cardiovascular Risk Management

There were 532 wristband wearable devices available online for purchase in Australia in 2020 which claimed to measure blood pressure but none of them were validated.

I am in the process of evaluating a very promising smart wearable made by a European company and not yet available in the US. This device has been validated as accurate and utilizes a calibration process against a simultaneous arm cuff BP measurement, something I felt would enhance the accuracy of all wrist-based BP devices. It utilizes a small lightweight bracelet for continuous and unobtrusive BP monitoring.

This device and others have the potential to improve our management of hypertension by providing the equivalent of 24-hour ambulatory home BP monitoring without the expense and hassle of currently available devices. Ambulatory BP monitoring is considered by some experts to be the gold standard for BP control.

Further studies are clearly needed before we can recommend cuffless monitoring but my sense is that we are very close to a breakthrough in this area.

Sphygmomaniacally Yours,

-ACP

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7 thoughts on “Are Wrist Blood Pressure Monitors Accurate? Can We Go Cuffless?”

  1. Measuring blood pressure has been one of the most frustrating aspects of my medical care. Many of the oscillometric devices in doctors office are as much as 50 mmHg higher than when the doctor takes it manually and I have found this for both myself and my mother. And I have found huge variation in home devices also. I have found some of the devices you recommend like the Omron Evolv to be totally unreliable. Even manual measurements by different people are different. I guess it is just because we are not doing a direct but rather an indirect measurement of blood pressure. The old mercury manometers seemed to give better results. Do you have any recommendations on how I could get accurate consistent measurements?

    Reply
    • Darrel,
      A lot of what you perceive as inaccurate measurement may be due to a marked lability of your blood pressure.
      Everyone has a fairly substantial minute to minute change in BP related to a variety of factors.
      Some have dramatic variations which we call labile hypertenison
      dr P

      Reply
  2. Dr Pearson,
    Thank you for this article. I do monitoring at home as am weaning off BP meds, which I was taking for svt. Thanks to ablation in December, fingers crossed, no svts..yet. I would LOVE for there to be a reliable cuff monitor but basically all the reviews, articles and research were thumbs down, so I ordered a nice Omron to replace my old bulky one. I want the most accurate results I can get, of course. One thing I cannot find in all my research is how to know if your cuffed upper arm is at heart level or not. The tables I use are about 30″ high but they feel too high. How does one know where to place that upper arm for best accuracy?? I don’t have a clue where in my chest my heart actually is and can’t find any info or videos that help. Any feedback would certainly be appreciated.
    Thank you for this excellent piece!

    Reply
  3. Very much looking forward to your review of the European wearable. I always have high BP at the doctor’s office (white coat syndrome) and low BP at home using an OMRON upper arm cuff. I read something lately about how those should be replaced every few years though. So we’re thinking of replacing ours. I take 25mg Troprol XL and 25mg Losartan for supposedly AFIB control (2 discrete episodes after high stress, 11.5 years apart) and have been taking them for over 15 years. I walk daily with my dog, albeit with my Trionic All Terrain Veloped rollator due to nerve pain in my leg from a back thing so need assistance walking if I want to walk any distance. Not as much exercise as I used to get but much grateful daily exercise nevertheless. So I “hope” that my home readings are accurate, not the readings at my occasional doctor visits…or Nurse Practitioner visits now that my doctor fled to back east. They don’t have enough doctors where I live and I’ve been informed that my NP (whom I like) is my new “doctor.” Tongue in cheek statement as far as I’m concerned but they don’t have a new doctor to replace the one they lost and none of their existing doctors have space. A sad situation for an elder like me. No chance of over treatment at least, eh?

    Reply
    • I’d be interested in the evidence that home BP monitor should be replaced “every few years.” That is not something I tell my patients.
      As to whether you will be under or over doctored by an NP versus an MD, I shall remain publicly neutral although I have a strong suspicion that one will occur in most cases.
      One thing I intended to include in my bp guide update but didn’t was the horrible technique for BP acquisition in most doctor’s offices. I have zero confidence in office-acquired BP.
      Therefor if a patient like you consistently presents me with good BP readings at home I trust those over anything we get in the office.
      Reasons are myriad

      dr P

      Reply
  4. When I first entered the BP arena I was getting a health checkup for a position with Procter & Gamble (I was 24) and my BP was 142/88 and I was told I would be dead by age 40. I went back for a recheck and the BP was 118/74, and they labeled me with “Transient Hypertension” and I was put on a drug called Rauwolfia (Raudixin) that kept the BP steady and just because of “genetics” my BP would fluctuate and when beta-blockers came along I was put on Corgard, with good results. Life went on and my ENT would take yearly ECG’s and after about 10 years he showed me the combined results as being IDENTICAL of a good heart pattern, and it was not until the great stress of my wife of 41 years dying that my BP was all over the place. I then developed A-Fib at age 77 which almost did me in…and now with a combination of the drugs of today and the vast improvement of medical knowledge and practice my BP is still monitored but without further incidence, and my EF increased from 52 to 60, and having been active all my life seems to have let me reach the age of 81, almost 82 with rather good health, and I only wish my Golf score would reflect my age…maybe some day it will.

    Reply
    • Towncar,
      Wow! I have only read of Rauwolfia, it had been replaced by better BP drugs by the time I started my training.
      Congratulations on making octogenarian status!
      And I hope you get a 90 on the golf course on your 90th birthday.
      Drl P

      Reply

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